Head Gasket Thickness

[79MaliCrazz]

I need help to figure out what gasket thickness i might need i dont have much specs cause i bought the car with this motor and was told minuimal info.Its a 350 chevy stock block with flat top piston the heads are stock just ported and polished 2.02/1.6 with roller rocker the cam specs are unknown so i really cant tell you compression of the motor.I hope that maybe you guys can help by the pics im posting.

 

[CHRIS.O]

What is your reason for replacing the head gasket? To order the proper set of gaskets you really should know if your block has been decked. You won't be able to figure that out unless you had the engine out and bare. So the next thing I would do which you can do with the engine in the car and assembled is measure the piston to valve clearance with no gasket between the head and block and not torqued just a few bolts around that cylinder you are measuring snugged. Also you need to know the combustion chamber size and if it has been altered, such as milling the heads. If you have barely any ptv clearance than you wouldn't want a steel shim .019 compressed thickness gasket. But if you had a ton of clearance that could make for bad quench and you might wanna fix that with a thin gasket. Hope I am making sense. If all else fails just run a .049 compressed thickness fel pro on it and don't look back.

 

[79MaliCrazz]

What is your reason for replacing the head gasket? To order the proper set of gaskets you really should know if your block has been decked. You won't be able to figure that out unless you had the engine out and bare. So the next thing I would do which you can do with the engine in the car and assembled is measure the piston to valve clearance with no gasket between the head and block and not torqued just a few bolts around that cylinder you are measuring snugged. Also you need to know the combustion chamber size and if it has been altered, such as milling the heads. If you have barely any ptv clearance than you wouldn't want a steel shim .019 compressed thickness gasket. But if you had a ton of clearance that could make for bad quench and you might wanna fix that with a thin gasket. Hope I am making sense. If all else fails just run a .049 compressed thickness fel pro on it and don't look back.

Im replacing the gasket due to head gasket issue had no compression in #3 and #5.As far as the head i dont know if it has been milled and the head is 76cc.Now how can i figure out what gasket is on there now i dont have any special tools.

 

[CHRIS.O]

I would just run down to your parts store and order a standard fel pro head gasket set for a chevy 350. The compressed thicknesses are labeled on the packaging. If you want to use a different thickness you could but it does not sound like the engine is anything crazy so I would not worry about getting too thin a gasket. If you have some calipers you could measure the cleanest nicest looking part of the old gasket and see how thick it is. It won't be perfect but should somewhat ball park you and you should be able to find a gasket that is close to that.

 

[G_Body_Enthusiast]

if you know the application for the engine (it came out of a 74 truck for example) that will give you information to give the guy across the counter so he can pull the right gaskets for your engine. now if you dont know what the application is you can go by the casting numbers and that will also help you find the right gaskets you need. casting numbers can tell you when the block was cast and what applications it was used for. i got lucky when i bought my shortblock, it has not been decked so the code on the passenger side deck surface was still there. so i know when it was cast and what it's applications were so i can get the right gaskets for it when (read: IF) i get it rebuilt. you also cant read the code on the passenger deck surface with the head in place and it is highly advised you replace BOTH head gaskets so you can get the code (if it's still there) when you remove the passenger side head.

if you have the codes that will help you immensely.

 

[olds307 and 403]

Check how far the pistons sit in the bore at tdc. .040" is a good number fom piston top to the cylinder head. If they are. 020" in the hole, get .020" head gaskets. Just try to hit the .040" as close as possible.

 

[79MaliCrazz]

Thanks guys I will look for the casting number and both heads are pulled.I will also measure the gap at tdc thanks.